(function flexible(window, document) {
  var docEl = document.documentElement;
  var dpr = window.devicePixelRatio || 1;

  // adjust body font size
  function setBodyFontSize() {
    if (document.body) {
      document.body.style.fontSize = 12 * dpr + "px";
    } else {
      document.addEventListener("DOMContentLoaded", setBodyFontSize);
    }
  }
  setBodyFontSize();

  // set 1rem = viewWidth / 10
  function setRemUnit() {
    // 这里默认是10等份，手动改为19.2，此时1rem=1920/19.2px即100px。（设计稿是1920px的） px转rem 需要 除100，例如：字体14px 转rem 0.14rem
    var rem = docEl.clientWidth / 19.2;
    const mixRem = 75
    if (rem < mixRem) {//由于最小字体大小是12px  限制最小缩放比例
      rem = mixRem
    }
    if (window && window.isOs) {
      docEl.style.fontSize = `${rem}px`;
      window.isOs().then((bool) => {
        docEl.style.fontSize = `${bool ? 100 : rem}px`;
      })
    } else {
      docEl.style.fontSize = `${rem}px`;
    }

  }

  setRemUnit();

  // reset rem unit on page resize
  window.addEventListener("resize", setRemUnit);
  window.addEventListener("pageshow", function (e) {
    if (e.persisted) {
      setRemUnit();
    }
  });

  // detect 0.5px supports
  if (dpr >= 2) {
    var fakeBody = document.createElement("body");
    var testElement = document.createElement("div");
    testElement.style.border = ".5px solid transparent";
    fakeBody.appendChild(testElement);
    docEl.appendChild(fakeBody);
    if (testElement.offsetHeight === 1) {
      docEl.classList.add("hairlines");
    }
    docEl.removeChild(fakeBody);
  }

  if (document.readyState === 'complete') {
    document.body.style.fontSize = '12px'
  } else {
    document.addEventListener(
      'DOMContentLoaded',
      (e) => {
        document.body.style.fontSize = '12px'
      },
      false,
    )
  }
})(window, document);